University of Illinois Urbana-Champaign

The Interstellar Medium Along The Life of Sight Toward X Per

Lien, David Jeffrey

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Description

Title
The Interstellar Medium Along The Life of Sight Toward X Per
Author(s)
Lien, David Jeffrey
Issue Date
1983
Department of Study
Astronomy
Discipline
Astronomy
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Physics, Astronomy and Astrophysics
Abstract
  • I have used ultraviolet, optical, and radio observations of the B0 V star X Per to analyze the physical conditions within the obscuring diffuse cloud. The ultraviolet data are from the International Ultraviolet Explorer satellite, the optical data are primarily blue echelle spectra, and the radio data are ('12)CO and ('13)CO J = 1-0 emission lines.
  • I observed more than 200 atomic and molecular UV absorption lines, and detected previously unobserved transitions from SiI, MgI, SI, ClI, FeII, GeII, and GaII. I also detected the O-O band of the F-X electronic system of C(,2). I derived a kinetic temperature of 40 K from a line profile analysis of this system. The electron density is 0.02 cm('-3). The hydrogen density ranges from 100 cm('-3) to 1000 cm('-3), depending on the method used to derive it.
  • I developed a simple model of this diffuse cloud based on the observed depletions, color excess, and total hydrogen column density. This model assumes the cloud is supported by turbulence. The model accurately predicts the neutral and dominant stage ion column densities, the average electron density, and the column densities of the fine structure lines of CI and CII. The density ranges from 35 cm('-3) at the edge of the cloud to 700 cm('-3) at the center. The mean electron density is 0.04 cm('-3), although the central region has n(,e) = 0.1 cm('-3). The data and the model are consistent with the existence of a velocity parameter gradient within the cloud, the effect of which is to produce the observed composite curve of growth.
Graduation Semester
1983
Type of Resource
text
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